This invention relates to concrete screeds and in particular to a portable screed which is guided by one or more operators to smooth freshly-poured concrete prior to finishing and curing. More particularly, the invention is directed to a screed which essentially floats on the surface of the plastic concrete as it is being tamped and leveled.
As explained in my co-pending U.S. patent application Ser. No. 006,895, filed Jan. 27, 1987, allowed tolerances for concrete surfaces have decreased, demanding greater precision in the smoothing and leveling of the concrete before it is cured. My co-pending application describes a laser-guided screed which can be operated to such close tolerances.
The screed of my co-pending application utilizes a screed plate similar to that commonly in use, having a width on the order of three inches. One problem encountered with the screed plate is the tendency of the screed to sink within the plastic concrete unless the operator carefully supports the screed during the screeding operation. For quite light screeds, constant supporting of the screed by the operator may not be a problem. However, for self-contained screeds, where the vibratory means is mounted on the screed, although the screed remains quite portable, the necessity for the operator to constantly lift the screed to retain its proper orientation can be quite tiring.